Key Concepts

• A test of a single variance can be a one-tail test or a two-tail test.
• The degrees of freedom for the test of a single variance is [latex]n-1[/latex].
• The test statistic is [latex]\frac{(n-1)s^2}{\sigma ^2}[/latex].

Glossary

Standard Deviation: A number that is equal to the square root of the variance and measures how far data values are from their mean; notation: [latex]s[/latex] for sample standard deviation and [latex]\sigma[/latex] for population standard deviation.